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          <th colspan="3" align="center">DB_ENV-&gt;cdsgroup_begin()</th>
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            <h2 class="title" style="clear: both"><a id="envcdsgroup_begin"></a>DB_ENV-&gt;cdsgroup_begin()</h2>
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      <pre class="programlisting">#include &lt;db.h&gt;

int
DB_ENV-&gt;cdsgroup_begin(DB_ENV *dbenv, DB_TXN **tid);  </pre>
      <p>
         The <code class="methodname">DB_ENV-&gt;cdsgroup_begin()</code> method allocates a locker ID in an
         environment configured for Berkeley DB Concurrent Data Store
         applications.  It copies a pointer to a 
         <a class="link" href="txn.html" title="Chapter 12.  The DB_TXN Handle">DB_TXN</a>  that uniquely identifies
         the locker ID into the memory to which <span class="bold"><strong>tid</strong></span> refers.  
         Calling the 
         <a class="xref" href="txncommit.html" title="DB_TXN-&gt;commit()">DB_TXN-&gt;commit()</a>  method will
         discard the allocated locker ID.
     </p>
      <p>
         See <a href="../../programmer_reference/cam.html#cam_intro" class="olink">Berkeley DB Concurrent Data Store applications</a> 
         for more information about when this is required.
     </p>
      <p>
        This method may not be called on a sliced database.
     </p>
      <p>
         The <code class="methodname">DB_ENV-&gt;cdsgroup_begin()</code> method may be called at any time during
         the life of the application.
     </p>
      <p>
         The <code class="methodname">DB_ENV-&gt;cdsgroup_begin()</code> <span>
            <span>
                  method returns a non-zero error value on failure and 0 on success.
            </span>
            
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              <h3 class="title"><a id="idm140711172445744"></a>Errors</h3>
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        <p>
             The <code class="methodname">DB_ENV-&gt;cdsgroup_begin()</code> <span>
            <span>
                 method may fail and return one of the following non-zero errors:
            </span>
            
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                <h4 class="title"><a id="idm140711172418640"></a>EINVAL</h4>
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                If this method is called on a sliced database;
                or if an invalid flag value or parameter was specified.
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                <h4 class="title"><a id="idm140711172418880"></a>ENOMEM</h4>
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          <p>
                The maximum number of lockers has been reached.
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              <h3 class="title"><a id="idm140711172420064"></a>Class</h3>
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        <p>
            <a class="link" href="env.html" title="Chapter 5.  The DB_ENV Handle">DB_ENV</a>, <a class="link" href="txn.html" title="Chapter 12.  The DB_TXN Handle">DB_TXN</a>  
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              <h3 class="title"><a id="idm140711172443664"></a>See Also</h3>
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             <a class="xref" href="txn.html#txnlist" title="Transaction Subsystem and Related Methods">Transaction Subsystem and Related Methods</a> 
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